Friday, May 1, 2015

The world smallest crak created by UCSD

Interesting work on making the smallest possible crack using graphene or so called nano gaps. In this case the use of single-layer graphene is used as a template
for the formation of subnanometer plasmonic gaps using a scalable
fabrication process called “nanoskiving.” The research was carried out by the University of California, San Diego (UCSD) and has been published in the journal Nano Letters.

This work demonstrates the use of single-layer graphene as a template
for the formation of subnanometer plasmonic gaps using a scalable
fabrication process called “nanoskiving.” These gaps are formed between
parallel gold nanowires in a process that first produces three-layer
thin films with the architecture gold/single-layer graphene/gold, and
then sections the composite films with an ultramicrotome. The structures
produced can be treated as two gold nanowires separated along their
entire lengths by an atomically thin graphene nanoribbon. Oxygen plasma
etches the sandwiched graphene to a finite depth; this action produces a
subnanometer gap near the top surface of the junction between the wires
that is capable of supporting highly confined optical fields. The
confinement of light is confirmed by surface-enhanced Raman spectroscopy
measurements, which indicate that the enhancement of the electric field
arises from the junction between the gold nanowires. These experiments
demonstrate nanoskiving as a unique and easy-to-implement fabrication
technique that is capable of forming subnanometer plasmonic gaps between
parallel metallic nanostructures over long, macroscopic distances.
These structures could be valuable for fundamental investigations as
well as applications in plasmonics and molecular electronics.